So, another problem. The screed on my floor doesn't touch the walls. There's some styrofoam between. I found out, that below the screed there's also styrofoam.
one of the problems is that the wall between the recording and the control room is just build on the screed. so there's styrofoam under my wall, styrofoam under my floor and the same styrofoam in the space between the screed and the walls. :bang
hmm, but that should be a floating floor, huh? :lol: maybe not a good one. :roll: well, i guess that floor should have it's own resonance frequence, that maybe, or should i say surely be in audible range? the screed should be about 3 or 4 cm.

the question is, how to deal with that? ripping out the screed, will most likely not be a option. this is just a little studio in a cellar, and at some point i will have to realize that i will have to make some compromise. sadly. So well, what could i do to deal with that, without spending a huge amount of time or money? any ideas?
the main preference will be internal sound - the isolation is ok, it isn't too good, but it's ok. but if i could do improvements on isolation without too much effort would be cool of course. but internal acoustics is much more of an issue.

hm, the only thing i can think at the moment is sealing the space between the floor and ceiling with silicone. but i'm not shure if that will help a lot concerning isolation. i guess that gap should be flexible because of the screed enlarging when getting warm.
concerning the resonance frequency, i think i should do some calculations. but there's probably not much, to improve that. maybe trying to add some mass.....

I see your message is couple of days old (previous one).
My problem was: I have no idea what this screed means (language thing).

The problem is if this is some kind of floating floar on polystyrene there's not much you can do.
You can lower MSM somewhat by adding mass, but nothing guarantees that the MSM will come low enough, meaning you just shifted the problem.

Ido once sent me polystyreen sold over there for floating floors and indeed it was polystyreen (I'M NOT A CHEMIST) or looked 99.5 % like it but felt as an elastic spring.
As such without the absorption (mainly closed cells) it was certainly a valid material for floating floors.

Anyhow, I never felt polystyreen like that (but of course there are much more things I don't know than know).

umm, another word for screed would be floor pavement - acording to my dictionary.
probably cast plaster floor would describe it more accurate. but i'm not 100% sure, that this word really describes the thing i have. but most likely it will.
I've been told that some polystrene was laid down on the concrete for thermal isolation (I guess, that i'm in a thermal isolation bomb shelter :lol: :lol: ) then the floor was made on this. about a few cm thick. but couldn't figure out what tape of polystrene it is.
so then, i will have to keep what i have - glue laminate on it, install absorbtion and hope it will be good?

If insulation is not the main issue, then indeed see it as a given and just continue as planned.
Otherwise do insulation measurements and check if the current situation is acceptable.

It's better to know now than after the whole studio is finished.
In function of priorities and what's important or not, you're the only one who can decide that.

If it is polystyreen most likely it's the standard expanded thermal type commonly known (there are different common densities but even the lowest is too rigid), which indeed is much too stiff for good acoustic floating floor applications. In that case indeed adding mass to the top floor won't help you (shifting problem a minor bit).

Ido once sent me polystyreen sold over there for floating floors and indeed it was polystyreen (I'M NOT A CHEMIST) or looked 99.5 % like it but felt as an elastic spring.

i've never seen anything quite like that. There are two common types of insulating polystyrene here in the US. The first is sort of "granular" in appearance, and is made up of discrete beads which you can see if you look.

the other kind is extruded, and has no discrete beads, and comes pink & blue in this part of the country.

the extruded type is far more stiff/rigid, i suspect that both types would exhibit compression-set beyond the acceptable for this application. (they'd compress and lose their resilience over time). The extruded stuff is essentially non-resilient.

a simple test to estimate if something is polystyrene: put a drop of toluene or xylene on it (naptha may also work). If it is styrene foam this will isntantly and horribly destroy the slab, eating a huge hole into the material immediately.

styrene is an aromatic vinyl polymer - it is exactly like polyethylene (which is commonly seen in trash bags and milk bottles) and polypropylene ( tupperware, rubbermaid, plastic dishware, many others), but with one small difference at one position in the repeating molecules

polyethylene is simply a hydrocarbon chain
polypropylene is just like polyethylene, but has a methyl group on every other carbon
polystyrene is just like polypropylene, but instead of the methyl group, it has an aromatic ring in the same position

and this difference of one of the 4 carbon spots on every other carbon in the chain has some interesting effects:

polyethylene is fairly soft, and almost un-breakable. At extreme molecular weights and very particular molecular arrangements THIS EXACT STUFF becomesabout the strongest material currently known, finding use even in applications like military equipment armor. At very low molecular weights it is common mineral spirits, or butane from a cigarette lighter, trash bags, blah blah blah

polypropylene is much harder, and polystyrene is extremely hard, water-clear, and very brittle.

the reactio to chemical is also interesting. Polystyrene foam is instantly soluble in toluene or xylene, but polypropylene has no known solvent at room temperatere at all, and is one of the most chemically resistant plastics.

anyone who is at all itnersted in the wild & crazy world of plastics/polymers should go to here:

that is one of the neatest, most effective, and most informative web sites i have ever seen.

Content posted by me is copyright 2004, 2005, 2006 Brian Ravnaas, but may be reproduced without permission for any non-commercial purpose so long as the intent is preserved. NRC Canada data is copyright them and used with permission, www.nrc.ca

all of these (and more) are the same thing - a continuous carbon chain with some stuff hanging off.

polyetheylene only has hydrogens hanging off, and is an almost mystically useful material with the aforementioned awesome range of properties. It is opaque (not see-through).

polystyrene is weak, brittle, water-clear, and degreades badly in sunlight and is relatively useless outside of a few specialty applications

teflon... the lowest coefficient of friction among common materials, almost infinite resistance to chemicals, radiation (sunlight), etc.

PVDF: used as formed-into-place paint on cars, and as an ultra-outdoor-durable coating on building steel

PVC: you may know it as plumbing pipe - a hard, fairly strong, fairly inert plastic. Or with plasticizers and copolymers, it is MLV, vinyl shower curtains, the dashboard of your car, the soft rubbery stuff on the handles of your tools, and more

and PVDC...? that is saran wrap - the cling wrap you store your food in (or it was anyway, they probably use a clarified polyethylene now)

without vinyl polymers, there would be no world as we know it.

Content posted by me is copyright 2004, 2005, 2006 Brian Ravnaas, but may be reproduced without permission for any non-commercial purpose so long as the intent is preserved. NRC Canada data is copyright them and used with permission, www.nrc.ca

Ido once sent me polystyreen sold over there for floating floors and indeed it was polystyreen (I'M NOT A CHEMIST) or looked 99.5 % like it but felt as an elastic spring.

i've never seen anything quite like that.

I never did either, that's why the material surpriced me and I asked Ido to send a sample.
For me it looked about as expanded polystyreen, but didn't feel like it.
And I know lots about the looks and feel (not chemics) of most common insulation materials.

(I worked for the acoustics division of an international industrial insulation company with in their top > 4000 employees, and for a certain resin type own production)

If insulation is not the main issue, then indeed see it as a given and just continue as planned.Otherwise do insulation measurements and check if the current situation is acceptable.

It's better to know now than after the whole studio is finished.In function of priorities and what's important or not, you're the only one who can decide that.

If it is polystyreen most likely it's the standard expanded thermal type commonly known (there are different common densities but even the lowest is too rigid), which indeed is much too stiff for good acoustic floating floor applications. In that case indeed adding mass to the top floor won't help you (shifting problem a minor bit).

The point is, i did use this rooms as a studio. i had some floor isolation material and thick wooden fibre sheet on the floor of that recording room . At this time isolation was ok. could have been better, but was ok. in my other thread scott told me to remove that wooden floor - most likely because of MSM. i guess this will lower TL again.
i also know that my door is a weak point regarding isolation. if i turn some music on in that room and walk into the control room, putting my ear on the wall, i can quite hear the music. if i do the same with the door - music is quite louder.
At this point figuring out how much the floor is an issue regarding isolation is hard to tell.
I thought about cutting the floor pavement along the wall that's inbetween the two rooms to decouple them better. but now i know that there's polystreen below, this seems not a good idea any more.

well, what could i do to improve isolation? it's just a matter how complex the job will be. i know this room ever will be a compromise. not only because of it's size. it's hard for me to accept this, but that's the way it is. and i've got to decide what job will be worth doing it regarding it's time-consumption and costs.

Ido once sent me polystyreen sold over there for floating floors and indeed it was polystyreen (I'M NOT A CHEMIST) or looked 99.5 % like it but felt as an elastic spring.

i've never seen anything quite like that.

I never did either, that's why the material surpriced me and I asked Ido to send a sample.For me it looked about as expanded polystyreen, but didn't feel like it.And I know lots about the looks and feel (not chemics) of most common insulation materials.

(I worked for the acoustics division of an international industrial insulation company with in their top > 4000 employees, and for a certain resin type own production)

always something new under the sun. i'd have probably hazarded a guess that styrene COULDN'T be used in this application.

at least i deal with being wron gpretty well on most days

Content posted by me is copyright 2004, 2005, 2006 Brian Ravnaas, but may be reproduced without permission for any non-commercial purpose so long as the intent is preserved. NRC Canada data is copyright them and used with permission, www.nrc.ca

You're in a situation that I don't like to gamble, but should measure to find the relative contribution of the different sound paths.
I'm sure Scott gave a solid advice based on the known data.
That's often the problem on the net, that it's not always that easy to put things in the right context.

If you want to do some comparative measurements you maybe can use a shaker that is used to feel rather than hear the bass music.
The Home Theater (edited: see below) guys know about them.
They like to get shaken by the music rather than listening to it.
They aren't expensive and it allows you to put a direct structure born signal on your floor.
The heavy shakers I saw on the net go as low as 40 Hz where they show their resonance frequency.

It's just an idea.

And don't listen only to the separating wall but also to the sound radiation of the floor and other walls.
Use a wooden block between your ear and the boundary you listen at.
Often you can relate the typical spectrum and level to the sound you hear in the receiving room itself.

The pro way to investigate this is using intensity measurements, but only for the intensity probe (mic) you can buy a lot of ETF programs.
For heavy massive walls you can do this also with accelerometers, but not or very inaccurate and lots of uncertainties for lightweight walls.

when i was talking to scott about the floor, i didn't know that there was that polystyreen underneath it. he just told me, i should take that wood out.
do you mean a subwoofer when talking about a shaker?
when i listen to the floor it is not as loud as the walls. but i guess loud bass and guitar amps standing on floor probably Bass drums, will be much more a problem, since everything is build on the same floor.
what do you think could be done to improve isolation? i just think knowing what could be done will ease the decision if something at all will be done.
if the only way to improve things will be very cost intensive and time consumpting, i will stick just to what i have - since i don't think it will be worth the effort, according to the rest of the room.

If you feel that your walls are the weak points,
I think you better shift the description you give to the walls, to see what's possible there.

Maybe you did that in another thread (please link then), but I don't memorize the whole forum ( Mostly I forget what I was doing a few minutes ago. At night I often wonder: "What the heck did I do today"? I'm the distracted type getting worse by aging.)

Edited:
You see: :wink: Forgot .......

A shaker is no subwoofer.
In fact you can see it as the core, the driver of a woofer/subwoofer which can be screwed to something.
So rather than exiting the membrane of the woofer which in its turn excites the air, you excite directly the object the shaker is screwed against.

So: it's a woofer without the membrane and speaker housing, adjusted to screw it directly to seatings, walls, floors, wherever.
The advantage for measuring is that you bypass the soundfield in your room which excites everything simultaneously and with much lower efficiency.

I've problems here with negatives/positives: So the shaker excites objects with much more efficiency, without creating those high soundlevels in the room.

the separating walls are of 3 layer of plasterboard on recording side and 2 layers on tracking side. they are screwed to the same aluminium studs with 100 mm rockwool inbetween. the weird thing about the walls are, that i feel they had better TLC immediately after building than now. but i have no measurment, so this might fool me. another weird thing regarding the walls is that they seem to transmit quiter sound better than loud noise. I had people in recording room, that heard what was spoken in tracking room. but loader sound isn't necessesarily louder in the other room

as you can see in the thread above, i've recently added the third layer of plasterboard on scotts advice. also, there are some resonances i'm fighting with. the floor isn't the only problem i have. :roll: :bang weird room....

Last edited by Nuuk on Sat Jan 29, 2005 2:41 pm, edited 1 time in total.

There are even DIY versions on the net (links I knew don't work anymore).
I was looking myself in the past for cheaper altenatives. Those things excist in Pro versions from B&K too. Gold is cheaper (matter of speech).
http://tinyurl.com/4q7lb

I told before but I still think it could be worthwhile to check in how far those things can be used for antinoise, better anti-vibration to improve TL.
Principle isn't new and is used already. Just in how far can such relative cheap things applied in studio use.

Last edited by Eric.Desart on Sat Jan 29, 2005 2:48 pm, edited 1 time in total.

the separating walls are of 3 layer of plasterboard on recording side and 2 layers on tracking side. they are screwed to the same aluminium studs with 100 mm rockwool inbetween. the weird thing about the walls are, that i feel they had better TLC immediately after building than now. but i have no measurment, so this might fool me. another weird thing regarding the walls is that they seem to transmit quiter sound better than loud noise. I had people in recording room, that heard what was spoken in tracking room. but loader sound isn't necessesarily louder in the other room

as you can see in the thread above, i've recently added the third layer of plasterboard on scotts advice. also, there are some resonances i'm fighting with. the floor isn't the only problem i have. weird room....

At a certain moment one must admit that a forum is not the right solution anymore to solve your problems.
This is typically something you need an expert on site.
This can start with a short not too expensive visit.

Then based on his thoughts and your available budgets, you can decide how far you will go.
This becomes that much gambling and assuming that even with the best of intents given advice can prove to be senseless, wrong and costly.

If this alu profile behaves as a wooden stud, then there could maybe something be done. e.g. demounting and make separate framing/remounting. But I said MAYBE.
Maybe the green Glue could help something, but again Maybe.
Maybe ............, but again maybe .........

It's like a doctor.
If you have a headache he gives you aspirine or comparable and tells you to relax more.
If that doesn't help, at a certain moment he must decide to do some tests before prescribing you all available, possible correct or not, drugs from the pharmacy.

I think seperate mounting would definitely improve TLC of the wall, but unmounting would be difficult, because each layer has been leveled, so finding the screws would be real hard. I think this project at the moment really goes far beyond where it should have been gone. When i started, i just wanted to get rid of a low frequency, that made my bass drum sound like Boooooooom. i was thinking of a helmholtz or similar.
I begann reading all the FAQ and stuff and got to the conclusion, that my previous treatment was just crap. So, i removed everything and started a thread concerning my concrete walls with thermal insulation on them. I ended up, putting a additional layer of plasterboard to my wall and removing my floor as well, what was ok but pretty more than i actually intended to do. then i got noticed about the issue concerning my floor. If there could be something done without too much effort to improve things - cool . if not - i will leave it.
This studio will never be a real commercial one. I will practise down there, sometimes recordiing something. sometimes recording a demo or maybe a cd with a band i'm playing with. I think recording a lot of other bands won't happen too often. just because i'm on the country here, and there aren't too many people, i could record. that's why isolation would be cool, but not too necessary.
Having an expert would probably be too expensive, just because the time one needs to get here and it's overdoing the thing i think. If having an expert here, it should have been done a few years ago, when all was started.
so, i'm greatful for every tip i could get here to improve what i've got a bit. Actually working here the recent years was ok. If i could improve something it would be good, otherwise i would leave it.

This sounds a bit disappointed.
I am really sorry that I couldn't be of more help. So are certainly the others too.

You still have the treatment issues I believe. So please feel free to ask.

If you should be able to do some pseudo TL measurements and the listening tests I described it could possibly tell something more already.
But without having any grasp to go on, it sometimes can be more helpful not to advice than to advice something.

Instead of having a subwoofer speaker cone excite the air -- which excites the entire room including the walls, a shaker is attached to the chair you are sitting in to deliver infrasonic (0hz to 20hz) and low frequency (20-250hz, although usually it's low filtered to just the 20hz to 80hz range) directly to your bones and thence to your ears. Since with a shaker you're not exciting the whole room, well there's less LF noise traveling to other rooms. ButtKicker advertises this as "Chick Friendly".

Originally shakers were intended to give physical effects to the person, e.g. during a DVD's depth charge explosion scene, but the ability to turn off the subwoofer when the kids are asleep was sort of discovered.

The two most popular types of shakers are:
a) The Butt Kicker which is bolted to the bottom of a chair, or inside of a (slightly decoupled) riser that your chair is sitting on. i.e., normally there's a solid floor, then the chair legs, then a couch spring with support beam, and you bolt the buttkicker to that support beam, and that flexes. Another 'bolt to the couch' style is Clark Transducerb) Crowson Technology TES 100 couch kit which instead of being bolted to the bottom of the couch, you simply lift the couch and set the couch's feet on a two of these. Certainly takes less time to install.